088122

We propose joint XMM-Newton openPar30ksclosePar and HST observations openPar3 orbitsclosePar of the nearby K young star V1298 Tau openParvirgul20MyrclosePar hosting four transiting exoplanets discovered with Kepler openParK2closePar comma and included in a follow-up optical-IR campaign with HARPS-N and GIANO-BarrobaTNG. These young planets have radii between 5.6 and 10.3 R_Earth and they are located between 0.08 and virgul0.3 AU from the host. They are still experiencing the contraction phase toward their final sizes and are subject to photoevaporation effects at different rates. Our immediate objective is to reconstruct the full XUV spectrum comma and to assess the spectral and time variability of the host star. In this way we will characterize its activity level and the dose of high- energy radiation received by those very young planets.